Reduced larsen effect electrode

ABSTRACT

The disclosure relates to a reduced Larsen Effect electrode. Specifically, the disclosure relates to an electrode with an insulation-coated electrode wire coaxially surrounded over a substantial portion thereof, by predetermined assembly of alternating rigid and isolating layers.

CROSS REFERENCE TO RELATED APPLICATIONS

This application Claim priority from U.S. provisional patent applicationNo. 62/144,042, filed Apr. 7, 2015 which is incorporated herein byreference in its entirety.

BACKGROUND

The disclosure is directed to a reduced Larsen Effect electrode.Specifically, the disclosure is directed to an electrode with aninsulation-coated electrode wire coaxially surrounded over a substantialportion thereof, by predetermined configuration of alternating rigid andisolating (or vibration dampening) layers.

Depth electrode recording systems are typically used in localizingsurgical targets for implantation of depth electrodes or for stimulatingand recording electrical signals from target regions in a tissue ororgan. Typically, these systems are in communication with depthelectrodes which are used for temporary stimulation and/or recording ofelectrical signals within a localized surgical site of a subject.

Commercially available depth electrodes are typically characterized by ahigh sensitivity for external noises with substantial microphonicfeedback effect between the system speakers and the depth electrode,which impedes signal integrity received from the depth electrode.

The microphonic feedback effect can be caused by at least one of thefollowing: positive feedback is generated once the speakers feedback tothe electrode and as a result saturates the amplifiers. Variousmechanical noise and vibration, such as motor vibration, motion of theelectrode within the tissue or voice of the subject, are detected by theelectrode that acts essentially as a microphone and is erroneouslycombined with the neural signal that is being recorded. It refers to therepercussion of the reception on the transmission, or of the output onthe input, phenomenon which is self-maintained in a closed loop(hereinafter, “Larsen Effect”), sometime to saturation.

Accordingly, accurate and high signal integrity (signal to noise ratio)of the electrode, is important in order to improve the effectiveness andefficiency of the electrode. Thus, there is a need in the field toprovide an electrode with reduced sensitivity to acoustic feedback.

SUMMARY

Provided herein are embodiments of reduced Larsen Effect electrodes.

In an embodiment, provided herein is a reduced Larsen Effect electrodeassembly for stimulation and/or recording of electrical signals in atissue or organ of a subject, the reduced Larsen effect Electrode havinga longitudinal axis, a distal end and a proximal end comprising: ashielding tube having an open proximal end and an open distal end, withan open stopper operably coupled to the distal end of the shieldingtube; a macro electrode sub-assembly coaxially coupled within theshielding tube, comprising: a rigidity-imparting macro cannula; and anisolating macro sleeve coaxially coupled thereon; and a micro electrodesub-assembly coaxially, slidably coupled within the macro electrodeassembly, comprising an insulation-coated electrode wire coaxiallycoupled along a portion thereof; to an isolating micro sleeve, coaxiallycoupled within a rigidity-imparting micro cannula

In yet another embodiment, the reduced Larsen Effect electrodesprovided, are configured such that at a fixed amplitude, the reducedLarsen Effect electrode produces noise level of no more than ±25 μV overfrequency range between 0.1 Hz and 7.0 kHz.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the reduced Larsen Effect electrode assembly relatingthereto described herein, will become apparent from the followingdetailed description when read in conjunction with the drawings, whichare exemplary, not limiting, and wherein like elements are numberedalike in several figures and in which:

FIG. 1A is a side view illustration of an embodiment of the reducedLarsen Effect electrode, with X-Z cross section taken along A-A in FIG.1A illustrated in FIG. 1B and enlarged portion B illustrated in FIG. 1C,with Z-Y cross section c in FIG. 1A, illustrated in FIG. 1D:

FIGS. 2A & 2B are respective simplified exploded view of a firstassembly stage (FIG. 2A) of a first part of a macro electrodesub-assembly (FIG. 2B) of the reduced Larsen Effect electrode assemblyshown in FIG. 1A;

FIGS. 3A & 3B are respective simplified exploded view of the assemblystage of the shielding tube of the reduced Larsen Effect electrodeassembly shown in FIG. 1A;

FIGS. 4A and 4B, illustrates the assembly of the macro electrodesub-assembly shown in FIG. 2B and the shielding tube illustrated in FIG.3B;

FIG. 5, illustrates the assembly of the elongated coupling member to theassembled shielding tube of FIG. 4B:

FIGS. 6A, 6B, illustrate the assembly of the insulating band onto theelongated coupling member illustrated in FIG. 5:

FIGS. 7A, 7B, and 7C illustrate the micro shielding assembly, of thedepth electrode shown in FIG. 1A:

FIGS. 8A and 8B, illustrate the assembly of the micro electrode assemblyinto the macro electrode sub-assembly disposed within the shieldingtube, attached to the banded elongated coupling member;

FIGS. 9A, 9B, and 9C, illustrate the assembly of another elongatedcoupling member with a collar;

FIGS. 10A and 10B illustrate a Y-Z cross section B of FIG. 1A (FIG. 10B)compared with typical electrode (FIG. 10A); and

FIG. 11, graph representing the noise levels sensed by the depthelectrode of FIG. 1A vs. the depth electrode illustrated in FIG. 10A.

While the disclosure is amenable to various modifications andalternative forms, specifics thereof have been shown by way of examplein the drawings and will be further described in detail hereinbelow. Itshould be understood, however, that the intention is not to limit thedisclosure to the particular embodiments described. On the contrary, theintention is to cover all modifications, equivalents, and alternatives.

DETAILED DESCRIPTION

The disclosure relates in one embodiment to reduced Larsen effectelectrodes.

The disclosure provides for an electrode with an insulation-coatedelectrode wire coaxially surrounded over a substantial portion thereof,by predetermined assembly of alternating rigid and isolating (orvibration dampening) layers. In other words, a depth electrode or multielectrode array, which is resistant to microphonic feedback effectcaused by one or more of the following and their combination; a positivefeedback is generated once the speakers feedback to the electrode and asa result saturates the amplifiers. Various mechanical noise andvibration, such as motor vibration, motion of the electrode within thetissue or voice of the subject, are detected by the electrode that actsas a microphone and is erroneously combined with the neural signal thatis being recorded.

Accordingly, provided herein is an electrode for stimulating orrecording of electrical signals while reducing Larsen effect, which canhave a micro electrode sub-assembly comprising in an embodiment, aninsulation-coated electrode wire with an isolating (and/or vibrationdampening) sleeve thereon, inserted in a rigidity-imparting microcannula. The rigidity-imparting can also be configured to provideprotection against electromagnetic interference (EMI), electrostaticdischarge (ESD), and radiofrequency interference (RFI). (As subsequentlyused herein “EMI” shall include ESD, RFI, and any other type ofelectromagnetic emission or effect). In addition, the rigidity-impartingmicro cannula decreases the flexibility of the wire, preventing thebuilding of a resonant wave in response to exposure to vibrationresulting from acoustic pressure on the electrode wire. The term“rigidity-imparting” represents the ability of the cannula to provide adegree of strength against bending or in other words, flexure rigidity.

The micro electrode sub-assembly is coaxially inserted into a macroelectrode assembly such that the micro electrode sub assembly isselectably slidably (in other words, telescopic sliding of the microelectrode sub-assembly within the macro electrode sub-assembly does notaffect the ability of the reduced Larsen effect electrode assembly)coupled and can be telescopically extended and retracted to providevariable sensing zone, or tip. The macro electrode sub-assembly iscompiled in the reverse order of the micro electrode assembly. In otherwords, a rigidity-imparting macro cannula has a sleeve of an isolatingmacro tube. The outer diameter of the rigidity-imparting micro cannulacan be configured to be between about 0.005 mm and 0.2 mm smaller thanthe inner diameter of the rigidity-imparting macro tube, thereby,leaving annular space between the rigidity-imparting tubes. Accordinglyand in an embodiment, the rigidity-imparting micro tube and therigidity-imparting macro cannula are separated by an annular space overa substantial portion of the longitudinal axis of the macro electrodesub-assembly (which is shorter than the micro electrode assembly)

Accordingly and in an embodiment, provided herein is a reduced LarsenEffect electrode assembly for stimulation and/or recording of electricalsignals in a tissue or organ of a subject, the reduced Larsen effectElectrode having a longitudinal axis, a distal end and a proximal endcomprising: a shielding tube having an open proximal end and an opendistal end, with an open stopper operably coupled to the distal end ofthe shielding tube; a macro electrode sub-assembly coaxially coupledwithin the shielding tube, comprising: a rigidity-imparting macrocannula; and an isolating (and/or vibration dampening) sleeve coaxiallycoupled thereon; and a micro electrode sub-assembly coaxially, slidablycoupled within the macro electrode assembly, comprising aninsulation-coated electrode wire coaxially coupled along a portionthereof; to an isolating micro sleeve, coaxially coupled within arigidity-imparting micro cannula.

In another embodiment, at least a portion of the macro electrodesub-assembly forming the reduced Larsen Effect electrode assembliesdescribed herein, can extend distally beyond the stopper of theshielding tube. In other words, and as described, the stopper coupled tothe shielding tube at the distal end can be open and the distal portionof the macro electrode sub-assembly can extend beyond (backwards ordistally, away from the tip) the stopper, creating a distal extension.Moreover, the portion of the macro electrode sub-assembly extendingdistally beyond the stopper of the shielding tube can be rotatablycoupled to a first elongated coupling member. In other words, theportion of the macro electrode sub-assembly extending distally beyondthe stopper of the shielding tube can form a hinge upon which theelongated coupling member can be coupled, allowing for rotation of theelongated coupling member (coupling to a power source e.g., or aprocessing module) around the portion of the macro electrodesub-assembly extending distally beyond the stopper of the shieldingtube. The first elongated coupling member extending therefore transverse(or, perpendicular) to the longitudinal axis of the reduced LarsenEffect electrode. As indicated, the first coupling member can beconfigured to communicate (or be in communication) with a first powersource, a first transceiver or a first device comprising one or more ofthe foregoing. The device can be, for example a signal processor forreceiving and analyzing the data recorded by the electrode, or providethe stimulation regimen required.

The term “signal processor” as used herein refers in an embodiment, to apower source, a pre-amplifier, an amplifier, an A/D and/or D/Aconverter, or a module or system comprising one or more of theforegoing. Likewise, the term “module” is understood to encompass atangible entity, be that an entity that is physically constructed,specifically configured (e.g., hardwired), or temporarily (e.g.,transitorily) configured (e.g., programmed) to operate in a specifiedmanner or to perform part or all of any operation described herein.Considering examples in which modules are temporarily configured, eachof the modules need not be instantiated at any one moment in time. Forexample, where the modules comprise a general-purpose hardware processorconfigured using software, the general-purpose hardware processor may beconfigured as respective different modules at different times. Softwaremay accordingly configure a hardware processor, for example, toconstitute a particular module at one instance of time and to constitutea different module at a different instance of time.

Further, term “communicate” (and its derivatives e.g., a first component“communicates with” or “is in communication with” a second component)and grammatical variations thereof are used to indicate a structural,functional, mechanical, electrical, or optical relationship, or anycombination thereof, between two or more components or elements. Assuch, the fact that one component is said to communicate with a secondcomponent is not intended to exclude the possibility that additionalcomponents can be present between, and/or operatively associated orengaged with, the first and second components. Furthermore, the term“electronic communication” means that one or more components of thereduced Larsen Effect electrode assemblies described herein, are inwired or wireless communication or internet communication so thatelectronic signals and information can be exchanged between thecomponents.

In addition, the first elongated coupling member used in the reducedLarsen Effect electrode assemblies described herein, can be furthercoupled to a first insulating band configured to cover a portion of thefirst elongated coupling member.

In an embodiment, at least a portion of the micro electrode sub-assemblyused in the reduced Larsen Effect electrode assemblies described herein,can be configured to extend distally beyond the distal end of the macroelectrode assembly. The portion of the micro electrode sub-assemblyextending distally beyond the distal end of the macro electrodesub-assembly can be operably coupled to and be in communication with asecond elongated coupling member, the second elongated coupling memberextending coaxially with the longitudinal axis of the reduced LarsenEffect electrode wherein the second coupling member is configured to bein communication with a second power source, a second transceiver or asecond device comprising one or more of the foregoing. For example, thefirst elongated coupling member can serve as a reference electrode andthe second elongated coupling member can serve as the stimulatingelectrode. In an embodiment, both elongated coupling members (first andsecond), can be coupled to the same signal processor. Likewise, thefirst coupling member can be operably coupled and be in communicationwith the second power source, second transceiver or second devicecomprising one or more of the foregoing and vice-a-versa.

Further, the distal end of the portion of the micro electrodesub-assembly extending distally beyond the distal end of the macroelectrode sub-assembly can be coupled to a micro collar.

In an embodiment, the insulation-coated electrode wire used in thereduced Larsen Effect electrode assemblies described herein, can be madeof tungsten. Alternatively, the insulation-coated electrode wire used inthe reduced Larsen Effect electrode assemblies described herein, can bemade of platinum iridium, pure iridium, stainless steel or the like.Likewise, the shielding tube and/or the rigidity-imparting macro tube,and/or the rigidity-imparting micro tube used in the reduced LarsenEffect electrode assemblies described herein, can be made of stainlesssteel or the like. Furthermore, the isolating (and/or vibrationdampening) macro sleeve and/or isolating (and/or vibration dampening)micro sleeve used in the reduced Larsen Effect electrode assembliesdescribed herein, can be made of a biocompatible thermoplastic polymer.The biocompatible, thermoplastic polymer can be, for example; polyimide,polyurethane, poly(divinylfluroride), a polycarbonate, anacrylonitrile/butadiene/styrene copolymer, a poly ether-ether ketone(PEEK), an epoxy, a nylon, or a copolymer and/or derivative thereofcomprising one or more of the foregoing.

Additionally, the rigidity-imparting macro cannula and/or isolatingmacro sleeve, used in the reduced Larsen Effect electrode assembliesdescribed herein, can each have a wall thickness between about 0.01 mmand about 1 mm such that the rigidity-imparting macro cannula abuts theisolating macro sleeve along the entire length of the isolating macrosleeve. Similarly, the rigidity-imparting micro cannula and/or isolatingmicro sleeve used in the reduced Larsen Effect electrode assembliesdescribed herein, can each have a wall thickness between about 0.01 mmand about 1 mm, such that the rigidity-imparting micro cannula abuts theisolating micro sleeve along the entire length of the rigidity-impartingmicro cannula.

The reduced Larsen Effect electrode assemblies described herein, areconfigured to produces noise level of no more than ±25 μV over frequencyrange between 0.1 Hz and 7.0 kHz, more specifically, noise level of nomore than ±10 μV over frequency range between 1.0 kHz and 4.0 kHz.

The depth probe described herein can be, for example, a stimulating andor recording electrode. Moreover, the reduced Larsen effect electrode,or electrode assemblies described herein can be configured to providedeep brain stimulation. Stimulating electrophysiological response and/orrecording electrophysiological evoked response using the electrodesdescribed herein can comprise stimulating, recording or both stimulatingand recording signals differentially, single ended or bothdifferentially and single ended. For example, a differential sensingconfiguration can include micro electrode sub-assembly as the sensingelectrode and the macro electrode sub-assembly used as a referenceelectrode. Typical tip-to-ring (exposed sensing portion of the macroelectrode assembly) spacing can be approximately 10 mm but may begreater or less than 10 mm. In an embodiment, the micro electrodesub-assembly of the reduced Larsen effect electrode assemblies providedherein, are configured to be slidably coupled to the macro electrodesub-assemblies, thus present variable measuring field length or, inother words, variable sensing portion (see e.g., element 150, FIGS. 1A,1B, 7C, 8B).

Other differential sensing configurations using any type of availableelectrodes can be used. During differential sensing, both the sensingelectrode and the reference electrode can be positioned along a mappedsite, such as within a brain region or along a nerve branch, such thatboth electrodes are subjected to change in electrical potential causedby an electrophysiological event in the brain.

Likewise, single ended sensing electrode configurations can comprise asensing electrode in contact with a region of interest, paired with areference electrode placed away from the region of interest, such thatthe reference electrode is not initially subjected to changes inelectrical potential caused by electrophysiological events occurring atthe site. In these circumstances, the macro isolating sleeve andrigidity-imparting macro cannula forming the macro electrodesub-assembly of the reduced Larsen Effect electrode assemblies describedherein can be configured to operate as a guide wire for the sensing,micro electrode sub-assembly (see e.g., element 107, FIG. 1B).

Recording the observation elements described herein can be configured tobe performed between two adjacent macro-contacts, for example a tipcontact and a ring macro contact spaced between about 20 μm and about500 μm from the tip contact (or electrode) by, for example, recordingdifferential local field potential (LFP) between the two contacts,wherein one contact is a reference to the other.

A more complete understanding of the components, processes, assemblies,and devices disclosed herein can be obtained by reference to theaccompanying drawings. These figures (also referred to herein as “FIG.”)are merely schematic representations (e.g., illustrations) based onconvenience and the ease of demonstrating the present disclosure, andare, therefore, not intended to indicate relative size and dimensions ofthe devices or components thereof and/or to define or limit the scope ofthe exemplary embodiments. Although specific terms are used in thefollowing description for the sake of clarity, these terms are intendedto refer only to the particular structure of the embodiments selectedfor illustration in the drawings, and are not intended to define orlimit the scope of the disclosure. In the drawings and the followingdescription below, it is to be understood that like numeric designationsrefer to components of like function.

Turning now to FIGS. 1A to 8B, illustrating reduced Larsen Effectelectrode assembly 100 for stimulation or recording of electricalsignals in a tissue or organ of a subject, reduced Larsen Effectelectrode assembly 100 having longitudinal axis X_(L), distal end 101and proximal end 103 (see e.g., FIG. 1A). Reduced Larsen Effectelectrode assembly 100 comprising: shielding tube 111 having openproximal end 131 and open distal end 133, with open stopper 112 (actingas a distal limit on the proximal movement of reduced Larsen Effectelectrode assembly 100 in a holder—not shown), operably coupled todistal end 133 of shielding tube 111 forming stoppered shielding tubesub-assembly 106 (see e.g., FIG. 3B). Reduced Larsen Effect electrodeassembly 100 further comprising macro electrode sub-assembly 130 havingproximal end 127 and distal end 129 (see e.g., FIG. 2B) coaxiallycoupled within stoppered shielding tube sub-assembly 106, comprisingrigidity imparting macro cannula 108 having isolating macro sleeve 110coaxially coupled thereon (see e.g., FIGS. IC, 2A). In an embodiment,isolating macro sleeve 108 can be a vibration dampening sleeve formed ofa biocompatible thermoplastic polymer, or co-polymer. The term“vibration dampening” is intended to be representative of a sleeve whichis capable of reducing vibrations in a sub-system. In anotherembodiment, stoppered shielding tube sub-assembly 106 is entirelymissing and macro electrode sub assembly 130 may be configured not tooperate as an electrode, but will rather operate as the shielding tube107 (see e.g., FIG. 1B) whereby shielding tube 107 will be a guide andprotect micro-electrode sub assembly 142 sensing zone 150 in proximalend 103. Under these circumstances and in another embodiment, reducedLarsen effect electrode assembly does NOT comprise first (or macro)elongated coupling member 114, first (or macro) elongated couplingmember 114 extending transverse to longitudinal axis (X_(L)) of reducedLarsen Effect electrode assembly 100, and will only comprise elongatedcoupling member 104, second (micro) elongated coupling member 104extending coaxially with longitudinal axis (X_(L)) of reduced LarsenEffect electrode assembly 100, operably coupled to the coated electrodewire 102 portion of micro electrode sub-assembly 142 extending distallybeyond distal end 129 of macro electrode sub-assembly 130, throughexposed isolating macro sleeve 118 at distal end 143 havingrigidity-imparting cannula 120 extending beyond isolating macro sleeve118, stoppered with micro collar 122, operating as a distal limit on theselectably slidable coupling of micro electrode sub assembly 142 withinmacro electrode sub-assembly 130. Accordingly and in an embodiment,micro collar 122 will abut distal end 129 on rigidity-imparting macrocannula 108 of macro electrode sub-assembly 130, thereby limiting theproximal movement of micro electrode sub assembly 142. The terms“selectably” or “selectably slidable” and similar grammaticalconfigurations, refer in an embodiment to the user choice in alteringsensing zone not affecting the operation of reduced Larsen Effectelectrode assembly 100.

Alternatively, stoppered shielding tube sub-assembly 106 is entirelymissing and macro electrode sub assembly 130 may be configured tooperate as an additional electrode. Under these circumstances and inanother embodiment, reduced Larsen effect electrode assembly doescomprise first (or macro) elongated coupling member 114, first (ormacro) elongated coupling member 114 extending transverse tolongitudinal axis (X_(L)) of reduced Larsen Effect electrode assembly100, as well as comprise elongated coupling member 104, second (micro)elongated coupling member 104 extending coaxially with longitudinal axis(X_(L)) of reduced Larsen Effect electrode assembly 100, operablycoupled to the coated wire electrode 102 portion of micro electrodesub-assembly 142 extending distally beyond distal end 129 of macroelectrode sub-assembly 130, through exposed isolating macro sleeve 118at distal end 143 stoppered with micro collar 122 as describedhereinabove

As illustrated in FIG. 2B, as assembled, in macro electrode sub-assembly130, rigidity imparting macro cannula 108 extend both proximally (forexample, between about 0.1 mm and about 3.0 mm) and distally (forexample, about 1.0 mm and about 10.0 mm) beyond isolating macro sleeve110. Reduced Larsen Effect electrode assembly 100 further comprisingmicro electrode sub-assembly 142 (see e.g., FIG. 7C), coaxially,slidably coupled within macro electrode sub-assembly 130, microelectrode sub-assembly 142 having insulation-coated electrode wire 102coaxially coupled along a portion thereof to isolating micro sleeve 118(see e.g., FIG. 7A), which is coaxially coupled in rigidity-impartingmicro cannula 120 (see e.g., FIG. 7B). In an embodiment, isolating microsleeve 118 can be a vibration dampening sleeve formed of a biocompatiblethermoplastic polymer, or co-polymer. As illustrated in FIG. 7C (and8B), proximal end 103 of micro electrode sub assembly 142 can beslidably coupled to macro electrode sub assembly 130, thus providingvariable sensing zone 150.

As illustrated in FIGS. 1B, and 9A-9C, at least a portion of macroelectrode sub-assembly 130 extends distally beyond stopper 112 ofshielding tube 111. As illustrated in FIG. 9A, isolating macro sleeve110 extends distally (away from the tip at proximal end 101), beyondstopper 112, further revealing rigidity-imparting macro cannula 108,extending further. As illustrated in FIGS. 1A, 5, 6A, 6B, and 9A, theportion of macro electrode sub-assembly 130 extending distally beyondstopper 112 of shielding tube 111 is rotatably coupled (see e.g., FIG.6A) to first (or macro) elongated coupling member 114, first (or macro)elongated coupling member 114 extending transverse to longitudinal axis(X_(L)) of reduced Larsen Effect electrode assembly 100 (see e.g., FIG.1A) wherein first (or macro) coupling member 114 is configured to be incommunication with a first power source, a first transceiver or a firstdevice comprising one or more of the foregoing. In an embodiment, atleast one of first (macro) or second (micro) elongated couplingmember(s) can be substituted by electrical wires, any other suitableconnectors or can alternatively be obviated entirely. As illustrated inFIGS. 6A, 6B, first elongated coupling member 114 is further coupled tofirst insulating band 116 configured to cover a portion of firstelongated coupling member 114.

Returning now to FIGS. 1B, 2A, 2B, 7A-7C, and 9A-9C, at least a portionof micro electrode sub-assembly 142 extends distally beyond the distalend 129 of macro electrode sub-assembly 130. As illustrated in FIGS. 1Band 9A-9C, rigidity-imparting micro cannula 120 extends distally (awayfrom tip proximal end 101) beyond distal end 129 of macro electrodesub-assembly 130, revealing isolation macro sleeve 118. As illustratedin FIG. 9B, the exposed isolating macro sleeve 118 at distal end 143 isfurther coupled to micro collar 122. As illustrated in FIGS. 7A-7C,electrode wire 102 extends proximally, beyond isolating micro sleeve 118between about 3.5 mm and about 4.5 mm, and beyond rigidity-impartingmicro tube 120, 2.5 and about 3.5 mm.

As illustrated in FIGS. 1B, and 9A-9C, the portion of micro electrodesub-assembly 142 extending distally beyond distal end 129 of macroelectrode sub-assembly 130 is operably coupled to second (micro)elongated coupling member 104, second (micro) elongated coupling member104 extending coaxially with longitudinal axis (X_(L)) of reduced LarsenEffect electrode assembly 100 wherein second (or micro) coupling memberconfigured to be in communication with a second power source, a secondtransceiver or a second device comprising one or more of the foregoing.As illustrated in FIG. 9A, micro collar 122 is operably coupled in anembodiment to rigidity imparting micro cannula 120, operating as adistal limitation on the forward or proximal selectably slidablemovement of micro electrode sub-assembly 142. As further illustrated inFIG. 9B, distal end 143 (see e.g., FIG. 7C) of micro electrodesub-assembly 142 exposes insulation-coated wire electrode 102, which canbe operably coupled to second (micro) elongated coupling member 104 (seee.g., FIG. 1B). As further illustrated in FIG. 9C, second insulationband 126 can partially cover micro collar 122. It is noted that firstand second insulation bands 116, 126 are optional and may not benecessary in all circumstances or embodiments.

Turning now to FIGS. 10A-10B, illustrating Y-Z cross section B of FIG.1A. As illustrated in FIG. 1A, of a typical electrode, wherein:

a is an insulation coated (OD₂ of 0.26 mm) microelectrode metal (OD₁ of0.254 mm);

b is micro isolation tube (OD₃ of 0.32 mm);

c is space (OD₄ of 0.36 mm);

d is macro metal tube (OD₅ of 0.56 mm); and

e is macro isolation tube (OD₆ of 0.7 mm).

Compared with FIG. 10B, illustrating the disclosed reduced Larsen Effectelectrode assembly 100, wherein insulation coated (OD₂ of 0.26 mm)microelectrode wire (OD₁ of 0.254 mm), has isolating micro sleeve 118(OD₃ of 0.34 mm), coaxially disposed rigidity-imparting micro(isolation) cannula 120 (OD₄ of 0.46 mm), with annular space 119 (OD₅ of0.51 mm), forming micro electrode sub-assembly 142, disposed withinrigidity-imparting macro (isolation) cannula 108 (OD₆ of 0.67 mm),having isolating macro sleeve 110 (OD₇ of 0.7 mm).

As illustrated, the disclosed electrode has an additional rigidisolation tube without increasing the overall diameter of the electrode.The results in terms of reduction in Larsen effect can be clearly seenin FIG. 11. which is a simplified graph representing the noise levelssensed by the depth electrode 100 of FIG. 1A vs typical prior art depthelectrode

As illustrated in FIG. 11, a speaker was placed in front of thereference electrode illustrated in FIG. 10A and in front of reducedLarsen Effect electrode assembly 100 constructed and operative inaccordance with an embodiment of the present disclosure. Thereafter, theamplitude (sound wave pressure, Db) was changed with the frequency scan.Maximum amplitude where at 800 Hz with amplitude of 90 Db; and a minimumof 30 Db at the amplitude of 9997 Hz. As illustrated, the amplitude israised from 50 Hz to 800 Hz and then reduced till the 9999 Hz. Theresulting noise value was measured and recorded by the electrodes. Theresulting graph illustrated in FIG. 11, represents the differencebetween noise level sensed and recorded by reduced Larsen Effectelectrode assembly 100 compared to the electrode illustrated in FIG.10A, as function of frequency and sound wave pressure. As illustrated,reduced Larsen Effect electrode assembly 100 produces noise level of nomore than ±25 μV over frequency range between 50 Hz and 7.0 kHz and nomore than ±10 μV over frequency range between 1.0 kHz and 4.0 kHz.

It can also be seen from the graph illustrated in FIG. 11, that in theelectrode illustrated in FIG. 10A the noise values as function offrequency reached values of more than 250 μV, whereas in reduced LarsenEffect electrode assembly 100 constructed and operative in accordancewith an embodiment of the present disclosure, the amplitude of the noisevalues as function of frequency only reached values of less than 25 μV,thus providing for approximately ten times noise feedback dampeningusing reduced Larsen Effect electrode assembly 100 disclosed herein.

Detailed embodiments of the present technology are disclosed herein;however, it is to be understood that the disclosed embodiments aremerely exemplary, which can be embodied in various forms. Therefore,specific structural and functional details disclosed herein are not tobe interpreted as limiting but merely as a basis for the claims and as arepresentative basis for teaching one skilled in the art to variouslyemploy the present technology in virtually any appropriately detailedstructure. Further, the terms and phrases used herein are not intendedto be limiting but rather to provide an understandable and enablingdescription.

The terms “first,” “second,” and the like, herein do not denote anyorder, quantity, or importance, but rather are used to denote oneelement from another. The terms “a”, “an” and “the” herein do not denotea limitation of quantity, and are to be construed to cover both thesingular and the plural, unless otherwise indicated herein or clearlycontradicted by context. The suffix “(s)” as used herein is intended toinclude both the singular and the plural of the term that it modifies,thereby including one or more of that term (e.g., the tube(s) includesone or more tube). Reference throughout the specification to “oneembodiment”, “another embodiment”, “an embodiment”, and so forth, meansthat a particular element (e.g., feature, structure, and/orcharacteristic) described in connection with the embodiment is includedin at least one embodiment described herein, and may or may not bepresent in other embodiments. In addition, it is to be understood thatthe described elements may be combined in any suitable manner in thevarious embodiments.

In addition, for the purposes of the present disclosure, directional orpositional terms such as “proximal”. “distal”, “top”, “bottom”, “upper,”“lower,” “side,” “front,” “frontal,” “forward,” “rear.” “rearward,”“back,” “trailing,” “above,” “below.” “left,” “right,” “horizontal,”“vertical,” “upward,” “downward.” “outer,” “inner,” “exterior,”“interior,” “intermediate.” etc., are merely used for convenience indescribing the various embodiments of the present disclosure.

One or more components may be referred to herein as “configured to,”“configured by,” “configurable to,” “operable/operative to,”“adapted/adaptable,” “able to,” “conformable/conformed to,” etc. Theterms (e.g. “configured to”) can generally encompass active-statecomponents and/or inactive-state components and/or standby-statecomponents, unless context requires otherwise.

Accordingly, provided herein is a reduced Larsen Effect electrodeassembly for stimulation and/or recording of electrical signals in atissue or organ of a subject, the reduced Larsen effect Electrode havinga longitudinal axis, a distal end and a proximal end comprising: ashielding tube having an open proximal end and an open distal end, withan open stopper operably coupled to the distal end of the shieldingtube; a macro electrode sub-assembly coaxially coupled within theshielding tube, comprising: a rigidity-imparting macro cannula; and anisolating (and/or vibration dampening) sleeve coaxially coupled thereon;and a micro electrode sub-assembly coaxially, slidably coupled withinthe macro electrode assembly, comprising an insulation-coated electrodewire coaxially coupled along a portion thereof; to an isolating microsleeve, coaxially coupled within a rigidity-imparting micro cannula,wherein (i) at least a portion of the macro electrode sub-assemblyextends distally beyond the stopper of the shielding tube, (ii) theportion of the macro electrode sub-assembly extending distally beyondthe stopper of the shielding tube is rotatably coupled to a firstelongated coupling member, the first elongated coupling member extendingtransverse to the longitudinal axis of the reduced Larsen Effectelectrode assembly, wherein the first coupling member is operablycoupled to the macro electrode sub-assembly and is configured to be incommunication with a first power source, a first transceiver or a firstdevice comprising one or more of the foregoing, (iii) the firstelongated coupling member is further coupled to a first insulating bandconfigured to cover a portion of the first elongated coupling member,wherein (iv) at least a portion of the micro electrode sub-assemblyextends distally beyond the distal end of the macro electrode assembly,(v) the portion of the micro electrode sub-assembly extending distallybeyond the distal end of the macro electrode sub-assembly is operablycoupled to a second elongated coupling member, the second elongatedcoupling member extending coaxially with the longitudinal axis of thereduced Larsen Effect electrode assembly wherein the second couplingmember is operably coupled to the micro electrode sub-assembly and isconfigured to be in communication with a second power source, a secondtransceiver or a second device comprising one or more of the foregoing.(vi) the distal end of the portion of the micro electrode sub-assemblyextending distally beyond the distal end of the macro electrodesub-assembly is operably coupled to a micro collar, wherein (vii)rigidity-imparting micro cannula; and the rigidity-imparting macrocannula are separated by an annular space, (viii) the annular space isabout 0.01 mm, wherein (ix) the micro electrode sub-assembly coaxially,slidably coupled within the macro electrode assembly is configured topresent a variable measuring area at the proximal end of the reducedLarsen Effect electrode assembly, wherein (x) the insulation-coatedelectrode wire is a tungsten wire, or (xi) of platinum iridium, pureiridium, or stainless steel, (xii) the shielding tube and/orrigidity-imparting macro cannula, and/or rigidity-imparting microcannula are made of stainless steel, (xiii) the isolation macro sleeveand/or isolating micro sleeve are made of a thermoplastic polymer, (xiv)the polymer is polyimide, polyurethane, poly(divinylfluroride), apolycarbonate, an acrylonitrile/butadiene/styrene copolymer, a polyether ether ketone, an epoxy, a nylon, or a copolymer and/or derivativethereof comprising one or more of the foregoing, wherein (xv) therigidity-imparting macro cannula and/or isolating macro sleeve, eachhave a wall thickness between about 0.01 mm and about 1 mm, (xvi) therigidity-imparting macro cannula abuts the isolating macro sleeve alongthe entire length of the isolating macro sleeve, wherein (xvii) therigidity-imparting micro cannula and/or isolating micro sleeve, eachhave a wall thickness between about 0.01 mm and about 1 mm, (xviii) therigidity-imparting micro cannula abuts the isolating micro sleeve alongthe entire length of rigidity-imparting micro cannula, wherein (xix) thereduced Larsen Effect electrode assembly produces noise level of no morethan ±25 μV over frequency range between 50 Hz and 7.0 kHz, or, morespecifically, noise level of no more than ±10 μV over frequency rangebetween 1.0 kHz and 4.0 kHz.

While in the foregoing specification the guidance systems for guiding abrain probe to a region of interest and their methods of facilitatinghave been described in relation to certain preferred embodiments, andmany details are set forth for purpose of illustration, it will beapparent to those skilled in the art that the disclosure can besusceptible to additional embodiments and that certain of the detailsdescribed in this specification and as are more fully delineated in thefollowing claims can be varied considerably without departing from thebasic principles of this invention.

1. A reduced Larsen Effect electrode assembly for stimulation and/orrecording of electrical signals in a tissue or organ of a subject, thereduced Larsen effect Electrode having a longitudinal axis, a distal endand a proximal end comprising: a. a shielding tube having an openproximal end and an open distal end, with an open stopper operablycoupled to the distal end of the shielding tube; b. a macro electrodesub-assembly coaxially coupled within the shielding tube, comprising: arigidity-imparting macro cannula; and an isolating macro sleevecoaxially coupled thereon; and c. a micro electrode sub-assemblycoaxially, selectably slidably coupled within the macro electrodeassembly, comprising an insulation-coated electrode wire coaxiallycoupled along a portion thereof to an isolating micro sleeve, coaxiallycoupled within a rigidity-imparting micro cannula.
 2. (canceled)
 3. Theassembly of claim 1, wherein at least a portion of the macro electrodesub-assembly extends distally beyond the stopper of the shielding tube,and wherein the portion of the macro electrode sub-assembly extendingdistally beyond the stopper of the shielding tube is rotatably coupledto a first elongated coupling member, the first elongated couplingmember extending transverse to the longitudinal axis of the reducedLarsen Effect electrode assembly, wherein the first coupling member isoperably coupled to the macro electrode sub-assembly and is configuredto be in communication with a first power source, a first transceiver ora first device comprising one or more of the foregoing.
 4. The assemblyof claim 3, wherein the first elongated coupling member is furthercoupled to a first insulating band configured to cover a portion of thefirst elongated coupling member.
 5. The assembly of claim 4, wherein atleast a portion of the micro electrode sub-assembly extends distallybeyond the distal end of the macro electrode assembly.
 6. The assemblyof claim 5, wherein the portion of the micro electrode sub-assemblyextending distally beyond the distal end of the macro electrodesub-assembly is operably coupled to a second elongated coupling member,the second elongated coupling member extending coaxially with thelongitudinal axis of the reduced Larsen Effect electrode assemblywherein the second coupling member is operably coupled to the microelectrode sub-assembly and is configured to be in communication with asecond power source, a second transceiver or a second device comprisingone or more of the foregoing.
 7. The assembly of claim 6, wherein thedistal end of the portion of the micro electrode sub-assembly extendingdistally beyond the distal end of the macro electrode sub-assembly isoperably coupled to a micro collar.
 8. The assembly of claim 1, whereinthe rigidity-imparting micro cannula; and the rigidity-imparting macrocannula are separated by an annular space.
 9. The assembly of claim 1,wherein the micro electrode sub-assembly coaxially, slidably coupledwithin the macro electrode assembly is configured to present a variablemeasuring area at the proximal end of the reduced Larsen Effectelectrode assembly.
 10. The assembly of claim 8, wherein the annularspace is between about 0.01 mm and about 0.2 mm.
 11. The assembly ofclaim 1 wherein the insulation-coated electrode wire is a tungsten wire.12. The assembly of claim 1, wherein said insulation-coated electrodewire is made of platinum iridium, pure iridium, or stainless steel. 13.The assembly of claim 1 wherein the shielding tube and/or therigidity-imparting macro cannula, and/or the rigidity-imparting microcannula are made of stainless steel.
 14. The assembly of claim 1,wherein the isolation macro sleeve and/or isolating micro sleeve aremade of a thermoplastic polymer.
 15. The assembly of claim 5, whereinthe polymer is polyimide, polyurethane, poly(divinylfluroride), apolycarbonate, an acrylonitrile/butadiene/styrene copolymer, a polyether ether ketone, an epoxy, a nylon, or a copolymer and/or derivativethereof comprising one or more of the foregoing.
 16. The assembly ofclaim 1 wherein the rigidity-imparting macro cannula and/or isolatingmacro sleeve, each have a wall thickness between about 0.01 mm and about1 mm.
 17. The assembly of claim 15 wherein the rigidity-imparting macrocannula abuts the isolating macro sleeve along the entire length of theisolating macro sleeve.
 18. The assembly of claim 1 wherein therigidity-imparting micro cannula and/or isolating micro sleeve, eachhave a wall thickness between about 0.01 mm and about 1 mm.
 19. Theassembly of claim 18 wherein the rigidity-imparting micro cannula abutsthe isolating micro sleeve along the entire length of therigidity-imparting micro cannula.
 20. The assembly of claim 1 whereinthe reduced Larsen Effect electrode assembly produces noise level of nomore than ±25 μV over frequency range between 0.1 Hz and 7.0 kHz. 21.The assembly of claim 19 wherein the reduced Larsen Effect electrodeassembly produces noise level of no more than ±10 μV over frequencyrange between 1.0 kHz and 4.0 kHz.